Insulin Resistance as a Potential Predictor of Post-Inflammatory Hyperpigmentation After CO₂ Laser Resurfacing: A...

Laser-assisted skin regeneration is a cornerstone of modern dermatologic practice; however, post-inflammatory hyperpigmentation (PIH) remains a major limiting complication of CO₂ laser treatments. Risk has traditionally been attributed to darker phototypes, particularly in high ultraviolet (UV) exposure settings. Emerging evidence suggests that metabolic factors, especially insulin resistance measured by HOMA-IR, may influence pigmentary responses. This study evaluated a Dual Technique CO₂ laser protocol designed to enhance skin regeneration while reducing the number of treatment sessions and explored the association between PIH and metabolic status.

A prospective, non-randomized, real-world study included 45 patients treated in a private practice in the Maghreb region, characterized by high UV exposure and predominantly medium-to-high phototypes. The Dual Technique combined ablative fractional vaporization with subablative thermal stimulation. Skin quality was assessed using the Vancouver Scar Scale (VSS), and PIH severity using the Dermal Pigmentation Area and Severity Index (DPASI). Outcomes were analyzed in relation to phototype, HOMA-IR, and polycystic ovary syndrome (PCOS).

Significant clinical improvement was observed across indications following treatment, typically within two sessions. PIH occurred in 15/20 (75%) patients with Fitzpatrick phototypes I-III compared with 9/25 (36%) patients with phototypes IV-VI (p = 0.0092). PIH severity showed a strong positive correlation with HOMA-IR (Spearman ρ = 0.8624, p < 0.0001). PCOS prevalence did not differ significantly between phototype groups (p = 0.8). PIH improved significantly following standardized management.

The Dual Technique CO₂ laser protocol was associated with favorable clinical outcomes using relatively few treatment sessions. In this cohort, higher HOMA-IR was strongly associated with greater PIH severity, suggesting that insulin resistance may represent an additional factor associated with individual PIH susceptibility. These findings are hypothesis-generating and require confirmation in larger, controlled studies before metabolic assessment can be recommended for routine laser-treatment risk stratification.